Changes in delay.h

a9ff6961 - ARM: mm: Make virt_to_pfn() a static inline

Thu, 02 Jun 2022 08:18:32 +0000

ARM: mm: Make virt_to_pfn() a static inlineMaking virt_to_pfn() a static inline taking a strongly typed(const void *) makes the contract of a passing a pointer of thattype to the function explicit and exposes any misuse of themacro virt_to_pfn() acting polymorphic and accepting many typessuch as (void *), (unitptr_t) or (unsigned long) as argumentswithout warnings.Doing this is a bit intrusive: virt_to_pfn() requiresPHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in, so this must be included *before* .The use of macros were obscuring the unclear inclusion order here,as the macros would eventually be resolved, but a static inlinelike this cannot be compiled with unresolved macros.The naive solution to include at the top of does not work, because sometimesincludes at the end of itself, which would create aconfusing inclusion loop. So instead, take the approach to alwaysunconditionally include at the end of arch/arm uses explicitly in a lot of places,however it turns out that if we just unconditionally include into and switch all inclusions of to instead, we enforce the rightorder and will always have access to thedefinitions.Put an inclusion guard in place making it impossible to include explicitly.Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/Signed-off-by: Linus Walleij List of files: /linux-6.15/arch/arm/include/asm/delay.h

b2441318 - License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Wed, 01 Nov 2017 14:07:57 +0000

License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseMany source files in the tree are missing licensing information, whichmakes it harder for compliance tools to determine the correct license.By default all files without license information are under the defaultlicense of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'SPDX license identifier. The SPDX identifier is a legally bindingshorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart andPhilippe Ombredanne.How this work was done:Patches were generated and checked against linux-4.14-rc6 for a subset ofthe use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up caseswhere non-standard license headers were used, and references to licensehad to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied toa file was done in a spreadsheet of side by side results from of theoutput of two independent scanners (ScanCode & Windriver) producing SPDXtag:value files created by Philippe Ombredanne. Philippe prepared thebase worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 filesassessed. Kate Stewart did a file by file comparison of the scannerresults in the spreadsheet to determine which SPDX license identifier(s)to be applied to the file. She confirmed any determination that was notimmediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines).All documentation files were explicitly excluded.The following heuristics were used to determine which SPDX licenseidentifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time.In total, over 70 hours of logged manual review was done on thespreadsheet to determine the SPDX license identifiers to apply to thesource files by Kate, Philippe, Thomas and, in some cases, confirmationby lawyers working with the Linux Foundation.Kate also obtained a third independent scan of the 4.13 code base fromFOSSology, and compared selected files where the other two scannersdisagreed against that SPDX file, to see if there was new insights. TheWindriver scanner is based on an older version of FOSSology in part, sothey are related.Thomas did random spot checks in about 500 files from the spreadsheetsfor the uapi headers and agreed with SPDX license identifier in thefiles he inspected. For the non-uapi files Thomas did random spot checksin about 15000 files.In initial set of patches against 4.14-rc6, 3 files were found to havecopy/paste license identifier errors, and have been fixed to reflect thecorrect identifier.Additionally Philippe spent 10 hours this week doing a detailed manualinspection and review of the 12,461 patched files from the initial patchversion early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correctThis produced a worksheet with 20 files needing minor correction. Thisworksheet was then exported into 3 different .csv files for thedifferent types of files to be modified.These .csv files were then reviewed by Greg. Thomas wrote a script toparse the csv files and add the proper SPDX tag to the file, in theformat that the file expected. This script was further refined by Gregbased on the output to detect more types of files automatically and todistinguish between header and source .c files (which need differentcomment types.) Finally Greg ran the script using the .csv files togenerate the patches.Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman List of files: /linux-6.15/arch/arm/include/asm/delay.h

207b1150 - ARM: 8619/1: udelay: document the various constants

Fri, 07 Oct 2016 04:38:35 +0000

ARM: 8619/1: udelay: document the various constantsExplain where the value for UDELAY_MULT and UDELAY_SHIFT come from.Also fix/clarify some comments pertaining to their usage in theassembly code.Signed-off-by: Nicolas Pitre Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

fb833b1f - ARM: fix delays

Wed, 05 Oct 2016 22:40:43 +0000

ARM: fix delaysCommit 215e362dafed ("ARM: 8306/1: loop_udelay: remove bogomips valuelimitation") tried to increase the bogomips limitation, but in doingso messed up udelay such that it always gives about a 5% error in thedelay, even if we use a timer.The calculation is: loops = UDELAY_MULT * us_delay * ticks_per_jiffy >> UDELAY_SHIFTOriginally, UDELAY_MULT was ((UL(2199023) * HZ) >> 11) and UDELAY_SHIFT30. Assuming HZ=100, us_delay of 1000 and ticks_per_jiffy of 1660000(eg, 166MHz timer, 1ms delay) this would calculate: ((UL(2199023) * HZ) >> 11) * 1000 * 1660000 >> 30 => 165999With the new values of 2047 * HZ + 483648 * HZ / 1000000 and 31, we get: (2047 * HZ + 483648 * HZ / 1000000) * 1000 * 1660000 >> 31 => 158269which is incorrect. This is due to a typo - correcting it gives: (2147 * HZ + 483648 * HZ / 1000000) * 1000 * 1660000 >> 31 => 165999i.o.w, the original value.Fixes: 215e362dafed ("ARM: 8306/1: loop_udelay: remove bogomips value limitation")Cc: Reviewed-by: Nicolas Pitre Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

215e362d - ARM: 8306/1: loop_udelay: remove bogomips value limitation

Wed, 25 Feb 2015 21:50:39 +0000

ARM: 8306/1: loop_udelay: remove bogomips value limitationNow that we don't support ARMv3 anymore, the loop based delay code canconvert microsecs into number of loops using a 64-bit multiplicationand more precision.This allows us to lift the hard limit of 3355 on the bogomips value asloops_per_jiffy may now safely span the full 32-bit range.Signed-off-by: Nicolas Pitre Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

6f3d90e5 - ARM: 7685/1: delay: use private ticks_per_jiffy field for timer-based delay ops

Thu, 28 Mar 2013 10:17:55 +0000

ARM: 7685/1: delay: use private ticks_per_jiffy field for timer-based delay opsCommit 70264367a243 ("ARM: 7653/2: do not scale loops_per_jiffy whenusing a constant delay clock") fixed a problem with our timer-baseddelay loop, where loops_per_jiffy is scaled by cpufreq yet used directlyby the timer delay ops.This patch fixes the problem in a more elegant way by keeping a privateticks_per_jiffy field in the delay ops, independent of loops_per_jiffyand therefore not subject to scaling. The loop-based delay continues touse loops_per_jiffy directly, as it should.Acked-by: Nicolas Pitre Signed-off-by: Will Deacon Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

70264367 - ARM: 7653/2: do not scale loops_per_jiffy when using a constant delay clock

Mon, 18 Feb 2013 15:36:13 +0000

ARM: 7653/2: do not scale loops_per_jiffy when using a constant delay clockWhen udelay() is implemented using an architected timer, it is wrongto scale loops_per_jiffy when changing the CPU clock frequency sincethe timer clock remains constant.The lpj should probably become an implementation detail relevant tothe CPU loop based delay routine only and more confined to it. In themean time this is the minimal fix needed to have expected delays withthe timer based implementation when cpufreq is also in use.Reported-by: Viresh Kumar Signed-off-by: Nicolas Pitre Tested-by: Viresh Kumar Acked-by: Liviu Dudau Cc: stable@vger.kernel.orgSigned-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

56942fec - ARM: 7538/1: delay: add registration mechanism for delay timer sources

Fri, 21 Sep 2012 17:51:44 +0000

ARM: 7538/1: delay: add registration mechanism for delay timer sourcesThe current timer-based delay loop relies on the architected timer toinitiate the switch away from the polling-based implementation. This isunfortunate for platforms without the architected timers but with asuitable delay source (that is, constant frequency, always powered-upand ticking as long as the CPUs are online).This patch introduces a registration mechanism for the delay timer(which provides an unconditional read_current_timer implementation) andupdates the architected timer code to use the new interface.Reviewed-by: Stephen Boyd Signed-off-by: Jonathan Austin Signed-off-by: Will Deacon Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

d0a533b1 - ARM: 7452/1: delay: allow timer-based delay implementation to be selected

Fri, 06 Jul 2012 14:47:17 +0000

ARM: 7452/1: delay: allow timer-based delay implementation to be selectedThis patch allows a timer-based delay implementation to be selected byswitching the delay routines over to use get_cycles, which isimplemented in terms of read_current_timer. This further allows us toskip the loop calibration and have a consistent delay function in theface of core frequency scaling.To avoid the pain of dealing with memory-mapped counters, thisimplementation uses the co-processor interface to the architected timerswhen they are available. The previous loop-based implementation iskept around for CPUs without the architected timers and we retain boththe maximum delay (2ms) and the corresponding conversion factors fordetermining the number of loops required for a given interval. Since theindirection of the timer routines will only work when called from C,the sa1100 sleep routines are modified to branch to the loop-based delayfunctions directly.Tested-by: Shinya Kuribayashi Reviewed-by: Stephen Boyd Signed-off-by: Will Deacon Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h

4baa9922 - [ARM] move include/asm-arm to arch/arm/include/asm

Sat, 02 Aug 2008 09:55:55 +0000

[ARM] move include/asm-arm to arch/arm/include/asmMove platform independent header files to arch/arm/include/asm, leavingthose in asm/arch* and asm/plat* alone.Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/include/asm/delay.h